Mexico to Build New Sinaloa Prison After 12 Deaths
SECURITY · MEXICO
Key Facts
- —The country Mexico, the southern neighbour of the United States. Sinaloa, a state on its Pacific coast, is the home base of the Sinaloa Cartel.
- —Why it matters Washington designated the Sinaloa Cartel a foreign terrorist organisation in 2025. The killings show its internal war now reaches deep inside state prisons.
- —Why now On Saturday 10 October Security Secretary Omar García Harfuch said the federal government will build a new Sinaloa prison with federal funds.
- —What happened Two clashes at El Castillo prison in Mazatlán on Thursday 8 and Friday 9 October killed 12 people, including a two-year-old boy visiting his father.
- —What it means for you Mazatlán is a beach resort popular with Americans. The prison is under reinforced federal guard, but 10 more people were shot dead across the city on Saturday.
- —Still open No exact site, budget or start date has been announced. Authorities have not said how firearms got into El Castillo.
Mexico’s federal government will build a new Sinaloa prison after two days of shootings inside the El Castillo jail in Mazatlán killed 12 people. Security Secretary Omar García Harfuch announced the project on Saturday 10 October. The dead include a two-year-old boy visiting his father, in the state at the centre of Washington’s fight against cartel drug trafficking.
García Harfuch heads the Security and Citizen Protection Ministry (SSPC), Mexico’s federal security ministry. He said President Claudia Sheinbaum had ordered the project. “By instruction of President Claudia Sheinbaum, the Government of Mexico will build, with federal funds, a new prison in Sinaloa,” he wrote on social media.
He said it would be “modern, safe and with the necessary infrastructure to strengthen prison control and help reduce violence in the state.” Until it exists, National Guard officers and federal prison staff are reinforcing El Castillo.
The Rio Times reported the first attack in Mazatlán Prison Riot Kills 10, Injures 16 and the second in Second Mazatlán Prison Riot Kills 2 Inmates. This report covers the federal response.
Two Days of Violence at El Castillo
The first clash broke out on the morning of Thursday 8 October in one of the prison’s modules. Sinaloa’s state Public Security Ministry said nine inmates and a two-year-old boy on a family visit died. At least 16 inmates were injured; State Attorney General Claudia Zulema Sánchez Kondo later put the number at 17.
State and federal forces entered the prison to retake control, and Navy aircraft flew over the site, the Sinaloa outlet Línea Directa reported. All visits were suspended.
Less than a day later, on Friday 9 October, a second fight left two more inmates dead. That brought the toll to 12, according to the state ministry.
The Sinaloa state prosecutor’s office is investigating. Sánchez Kondo said the inquiry would be broad and would examine how the weapons got inside.
The Cartel War Behind the Shootings
Federal authorities told El Universal that the Thursday attack aimed to kill Eduardo Martínez Larios, known as “El Owen.” They described him as an operator for Los Chapitos, the faction led by sons of jailed drug lord Joaquín “El Chapo” Guzmán.
The state prosecutor had not formally confirmed his identity by Friday. Sánchez Kondo said families had not yet completed official identifications of the dead.
Los Chapitos have fought La Mayiza, the faction loyal to Ismael “El Mayo” Zambada, since 2024. Both are wings of the Sinaloa Cartel, and their feud has spilled from the streets into the prisons.
The prisons have been a front before. Two inmates died at El Castillo on 24 September. Seven were killed at Aguaruto prison in Culiacán on 31 May, El Financiero reported, citing the state prosecutor.
Mexico’s National Human Rights Commission (CNDH), the federal rights ombudsman, scored El Castillo 5.25 out of 10 in its 2025 prison review. It flagged too few guards and poor separation of inmates awaiting trial from those already sentenced.
What the New Sinaloa Prison Plan Includes
García Harfuch thanked Sinaloa’s interim governor, Graciela Domínguez Nava, for offering the land. She has said several possible sites are under study in Culiacán, the state capital.
The state government first disclosed the plan on Friday. Domínguez called it “an advance” that confirms both governments will keep working together for “well-being, justice and peace in Sinaloa.”
No budget, capacity or start date for the new Sinaloa prison has been published. El Financiero noted that tendering, permits and construction could take years.
Meanwhile, life inside El Castillo is resuming under guard. The state ministry said family visits restarted on Saturday and will continue on Sunday 11 October. An inter-agency group from all three levels of government is still searching the prison.
What It Means for You
For American readers, the main link is the cartel. The US government designated the Sinaloa Cartel a foreign terrorist organisation in February 2025. US officials name it as a main source of the fentanyl reaching American cities.
The stabiliser is federal control. A federally funded Sinaloa prison could move high-risk inmates out of a state system that the CNDH rated poorly. The risk is time: the new site does not exist yet, and El Castillo stays in use.
Mazatlán is one of Mexico’s main Pacific resorts and a regular cruise stop. The prison shootings stayed inside its walls, but the city’s streets are not calm. El Universal reported on Saturday 10 October that gunmen killed 10 more people, one of them a woman, in separate attacks in residential neighbourhoods such as Independencia, Alborada and Palos Prietos. Travellers should read the State Department’s current advisory for Sinaloa before going.
Hurricane Simón is also approaching Mexico’s Pacific coast this weekend. Anyone with plans in the region should watch airline and port notices.
What Is Not Known
It is not known exactly where the new prison will stand, what it will cost or when work will begin.
Authorities have not said how firearms entered El Castillo, or whether any staff helped. No arrests over the two attacks have been announced.
The full list of the dead has not been officially published, and the reported target’s death awaits formal confirmation. It is also not known whether Saturday’s street killings in Mazatlán are linked to the prison attacks.
Frequently Asked Questions
What happened at the Mazatlán prison?
Two clashes at El Castillo prison on 8 and 9 October killed 11 inmates and a two-year-old boy who was visiting his father, Sinaloa’s state security ministry said.
What did the federal government announce?
Security Secretary Omar García Harfuch said on 10 October that Mexico will build a new prison in Sinaloa with federal funds. National Guard officers are reinforcing El Castillo meanwhile.
Is Mazatlán safe for tourists?
The prison violence stayed inside El Castillo, but 10 more people were shot dead in separate attacks across Mazatlán on Saturday, El Universal reported. Travellers should check the US State Department’s current advisory for Sinaloa before travelling.
Sources: El Universal (Harfuch announcement) · El Universal (El Owen, CNDH review) · El Financiero · Línea Directa (federal reinforcement) · Línea Directa (visits resume) · El Universal (Saturday street killings) · Infobae México
Editorial responsibility: Matthias Camenzind, Editor-in-Chief · Editorial standards · Report an error